Cancer patients who undergo radiation therapy or chemotherapy often become infertile. While post-pubescent men have the option of preserving sperm before cancer treatment to use at a later date, boys who have not yet matured do not have that luxury. Since their bodies have not yet produced sperm, they often face a lifetime of infertility.

The new study is led by Kyle Orwig of the University of Pittsburgh and Magee-Womens Research Institute. Orwig and his team preserve spermatogonial stem cells (SSC) – the cells that will later develop into sperm – from a group of monkeys. After treating the monkeys with a commonly used chemotherapy drug, the injected the preserved SSCs into the monkey’s testicles. In the majority of the monkeys, the cells produced healthy and productive sperm. Even more importantly, the SSC-derived sperm of one animal “was capable of fertilizing egg cells and producing embryos that developed normally.”

“This is the first study to demonstrate that transplanted spermatogonial stem cells can produce functional sperm in higher primates,” Orwig stated. “This is an important step toward human translation.”

The promising strategy resulting from the recent study is this: Now, boys who are not yet mature may preserve their SSCs through a process called cryopreserving. After they have finished cancer treatment, the preserves cells can be injected, and – the hope is – develop into viable sperm. This approach has worked in a range of animal models, but past studies in large animals have primarily used radiation therapy to cause infertility, even though chemotherapy is also a common source of infertility in cancer patients.